Hormonal interplay during adventitious root formation in flooded tomato plants

MARÍA LAURA VIDOZ; ELENA LORETI; ANNA MENSUALI; AMEDEO ALPI; PIERDOMENICO PERATA

Volterra. Italia

Congreso; International Society of Plant Anaerobiosis Congress; 2010

International Society of Plant Anaerobiosis

The primary effect of soil flooding is a decrease in gas exchange, which negatively affects oxygen supply to submerged tissues and may result in plant death. Although rice is a crop species particularly tolerant to submergence, many others are highly sensitive to the excess of water in the soil profile, probably because flooding resistance has not been one of the main objectives in improvement programs of most cultivated plants. This is the case of tomato (Solanum lycopersicum L.), a waterlogging sensitive plant whose ability to produce adventitious roots (AR) increases its chances to survive root hypoxia. The application of ethylene-biosynthesis inhibitor aminoethoxyvinylglycine (AVG) and 1-naphthylphthalamic acid (NPA), an auxin transport inhibitor, resulted in a reduction of AR formation in waterlogged plants suggesting that ethylene and auxin may interact to elicit AR production in flooded tomato. These results were confirmed using tomato mutants for ethylene and auxin perception (Never ripe and Diageotropica, respectively). Ethylene and auxin quantification in submerged and non-submerged tissues indicated that ethylene entrapment by water, besides warning the plant about the presence of waterlogging, would stimulate auxin transport. Auxin accumulation in the stem triggers additional ethylene synthesis and facilitates auxin movement towards the flooded parts of the plant. In this way, preformed root initials are induced to grow in submerged stem areas, resulting in a new root system that replaces the original one when it has been damaged by flooding-induced hypoxia.